[mel4fun]

Hi,

Thanks for the advice.

Problem found, and a silly mistake.

There is a static route on the Nokia for Host A, but pointing to the wrong interface. Instead of pointing inwards, it was pointing outwards to the external router.

Therefore, when we initiate the TCP 3140 from Host A, the return TCP ACK from Host C never return, thus the error.

The TCP ACK is bouncing between the firewall external and router interface.

Silly mistake but glad that we resolve it.